1. Field of the Invention
The present invention relates to trays for holding material used to make impressions of teeth and gums.
2. Description of the Prior Art
When a dentist makes an impression of a patient""s teeth and/or gums, he or she places a temporarily viscous compound called an xe2x80x9cimpression materialxe2x80x9d over the teeth and gums in each jaw. To obtain an accurate impression, the impression material must be pushed against the teeth and gums, so that there are no gaps between the teeth and gums and the impression material. After the impression material has hardened enough to retain its shape, it is then removed and used as a mold. It is customary to place the compound in a tray before it is placed over the teeth and gums. Dental impression trays are shaped to fit over the teeth and gums in a jaw.
It is desirable to have an improved method of retaining the impression material in the tray before it hardens. It is sometimes necessary to make an impression of teeth on only one side of a jaw. It is also sometimes desirable to have an opening in the tray, especially when work is being done on dental implants. It is sometimes necessary in surgical situations to make an impression of the occlusal (biting or grinding) half of the teeth and certain implant components while avoiding contact with the underlying tissue. It will be seen that the present invention meets these needs better than the prior art.
U.S. Pat. No. 53,347, issued on Mar. 20, 1866, to George F. Schaffer, discloses a dental impression cup with detachable bottom sections.
U.S. Pat. No. 98,066, issued on Dec. 21, 1869, to Robert V. Jenks, discloses one of the first dental impression trays to be patented, made in two separate pieces, which is divided in the middle as is the present invention. The two separate pieces can be joined by lugs and a clamping screw, or by other means. The instant invention is distinguishable, in that it has a different means of attaching the two halves, which cannot be rejoined when separated.
U.S. Pat. No. 1,489,192, issued on Apr. 1, 1924, to Ernest A. Cleveland, discloses an adjustable dental tray with removable side walls.
U.S. Pat. No. 1,499,482, issued on Jul. 1, 1924, to Henry Charles Simmons, discloses another dental impression tray having two halves, which are joined by a clamping screw.
U.S. Pat. No. 1,652,910, issued on Dec. 13, 1927, to Joseph E. Psayla, discloses a registering bite tray, having rectangular perforations similar in shape to the gap made when one of the detachable panels in removed from the present invention. The instant invention is distinguishable, in that it has detachable panels, so that the position of the openings can be varied to suit patient""s circumstances.
U.S. Pat. No. 3,626,594, issued on Dec. 14, 1971, to Ira D. Zinner and Herbert Sherman, discloses a dental impression tray having separable end portions.
U.S. Pat. No. 3,878,610, issued on Apr. 22, 1975, to William Alfred Coscina, discloses a low profile dental impression tray, with vertical score lines through which sections of the tray can be broken off.
U.S. Pat. No. 3,978,585, issued on Sep. 7, 1976, to Burton V. Holcomb, discloses a dental impression tray with numerous perforations and a handle extending from the front.
U.S. Pat. No. 4,368,040, issued on Jan. 11, 1983, to Bernard Weissman, discloses a dental impression tray, which in one embodiment has two halves that can be locked together.
U.S. Pat. No. 4,432,728, issued on Feb. 21, 1984, to Floyd E. Sharky, discloses a dental tray with vertical grooves along which sections of the tray can be broken off.
U.S. Pat. No. 4,689,010, issued on Aug. 25, 1987, to Herbert Wolfe, discloses a dental impression tray with xe2x80x9cribsxe2x80x9d on the inside surfaces of the sidewalls.
U.S. Pat. No. 5,336,086, issued on Aug. 9, 1994, to Christian Simmen and Nathaniel H. Lenchner, discloses a dental impression tray, having numerous perforations, and ribs elevated above the inside bottom surface between the walls of the tray.
U.S. Pat. No. 5,340,308, issued on Aug. 23, 1994, to Joseph F. Cukjati, discloses an adjustable dental tray with sliding portions that enable its shape to be adjusted to fit the shape of the mouth of the patient. (This tray is designed for mammals in general, not primarily for humans.)
U.S. Pat. No. 5,551,872, issued on Sep. 3, 1996, to Raul Mena, discloses a dental impression device having a housing member with openings in an upper wall, and a cover member.
U.S. Pat. No. 5,890,895, issued on Apr. 6, 1999, to John Hilliard Tucker, discloses a dental impression tray, with a handle and a mouth piece having various perforations through which excess impression material is extruded and interlocks to secure the impression material to the mouthpiece.
International patent application Ser. No. WO 92/3985, published on Mar. 19, 1992, discloses a dental modeling method and apparatus using an apertured matrix plate.
Austrian Patent No. 149,778, issued on May 25, 1937, to Alfred Pelzmann and Karl Kaindlstorfer, discloses a dental impression tray with a handle and holes or slits through which excess impression material can flow.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The invention is an improved dental impression tray, with several unique features: 1. A crease or line of perforations running through the middle of the tray (where it is placed over the front part of an upper or lower jaw) and the middle of the tray""s handle, so that the tray can easily be broken in half, if an impression of only one side of a jaw needs to be taken. (There may also be additional creases or lines of perforations situated in vertical planes perpendicular to the circumference of the tray, so that fractions of the tray smaller than one half can be detached to take an impression of less than one half of a jaw.) 2. Ridges or protrusions on opposite interior walls of the tray, to better retain the rapidly hardening semi-fluid material with which the impressions of the teeth and/or gums are taken. 3. Base panels of the tray separated from the walls of the tray by gaps around their perimeters, and connected only by narrow strips of the material from which the tray is made, so that the base panels can be easily detached when desired, thus creating an opening in the occlusal aspect (or bottom) of the tray that may be desirable for certain forms of dentistry, especially work involving dental implants. 4. A crease or line of perforations running just above the ridges or protrusions, to facilitate easy and clean removal of a flange extending above the ridges or protrusions.
Accordingly, it is a first object of the invention to provide a means of taking an impression of only one side of a jaw.
It is a second object of the invention to reduce the size of the dental impression tray to the minimum size necessary.
It is third object of the invention to provide a means of retaining impression material more securely in the impression tray.
It is a fourth object of the invention to provide an improved means of making one or more openings in an impression tray.
It is a fifth object of the invention is to provide an impression tray which is useful in work on dental implants.
It is a sixth object of the invention to provide a method of quick and easy removal of the buccal and lingual (inner and outer) flanges without creating small grindings of the parent material or the cutting material so as to keep the surgical site clean.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.